Process timer



Feb. 23, 1943. 5. P. COWLES PROCESS TIMER Filed NOV 25, 1941 Inventor: George Cowles, b W His ttorney Patented Feb. 23, 1943 rnocnss TIMER George P. Cowles, Framingham, Mass, assignor to Warren Telechron Company, a corporation of Maine Application November 25, 1941, Serial No. 420,365

6 Claims.

My invention relates to process timers and in particular to a process timer which, upon completion of its timing operation, resets or reconditions itself for a repeat operation.

The features of my invention which are believed to be novel and patentable will be pointed out in the claims appended hereto. For a better understanding of my invention, reference is made in the following description to the accompanying drawing in which Fig. 1 represents an exploded perspective view of a preferred form of my invention; Fig. 2 represents a side view, partially in section, of the mechanism of Fig. 1 but in a more compact'asse'mbly; and Figs. 3, 4 and represent modified release mechanisms which may take the place of the magnetic release device 34 of Fig. 1.

Referring now to Fig. l, at it I have represented a panel provided with a plurality of stationary contacts ll. Such stationary contacts may be provided both on the front and rear of the panel ill. Cooperating with such stationary contacts are a plurality of movable contact fingers l2. l3 designates a contact finger coopcrating with a stationary contact on the rear of panel l0. l4 represents a rotary member of insulating material having a plurality of raised cam surfaces such as l5 and 41 adapted to be rotated beneath the various contact fingers to open and close the contacts at H. The number and sequence operating arrangement of the various contacts and cam operating members will vary, depending upon the nature of the process to be controlled. For example, the controller may be arranged to control the various operations of an automatic electric dishwashing machine, the washing machine process being started by a push button or the like. It is intended that the rotary controller member M will make substantially one complete revolution in a clockwise direction between initial and final positions during a process timing operation in a certain prescribed time and at the end of such time rotate quickly in a counter-clockwise direction to its initial position and be ready to repeat the timing process. 7

The rotary controller is mounted on a shaft l6, which shaft also carries a stop finger H which, in the initial or zero position represented, rests against a stationary stop l8, which stop may be made adjustable for controlling the time of the total cycle. During a process timing operation the rotary controller I4 is rotated in a clockwise direction by a timing motor I9 which may be a synchronous motor of the unidirectional self-starting type. The motor is connected to drive shaft 16 through a gear train which includes differential gearing, the central member of which is designated 20. Thus, if member 20 is held from rotation, the motor drive comprises shaft 2|, gears 22, 23, 24, 25, shaft 26, gears 21, 28 and 29. The shaft 26 has a bearing in and is carried by the differential member 2|]. Gears 24 and 28 have the same axis of rotation as'differential member 20 but these three members are rotatable independently of each other on such axis.

It is now evident that when differential member 20 is held stationary and the motor I9 is operating in the direction indicated by the arrow adjacent its terminal shaft, controller member l4 will be rotated in a clockwise direction.

Also secured to shaft l6 of the rotary controller I4 is the outer end of a spiral spring 30, the connection being through a connecting drum 3| secured to shaft [6. The inner end of spring 30 is held by a stationary sleeve 32. Hence, when the controller member I4 is rotated in a clockwise direction by motor IS, the spring 30 is wound up. The purpose of spring 30 is to rotate controller member l4 in a counter-clockwise direction'and return it to a zero or initial position at the end of a process timing operation.

The motor l9 may not have its rotor operated in the reverse direction by the spring even when the motor is deenergized primarily because of the high gear reduction contained within the gear casing at 33. Hence, in'order for the controller member l4 to be rotated counter-clockwise by spring 30, the differential member 20 is released and allowed to rotate in the direction indicated by the arrow thereon.

Diiferential member 20 is controlled or normally held from rotation when the motor I8 is energized by a magnetic lock 34 which is magnetically held in the position shown when the motor i9 is energized by reason of the diversion of a portion of the motor field fiux through auxiliary pole pieces 35 and 36 branched off from the motor field core 31 on opposite sides of its field coil 38. This magnetic lock or fiy 34 is rotatively mounted between the auxiliary pole pieces 35 and 36 and is geared to the differential member 20 as shown through a suitable gear train 39. When the motor is deenergized, the magnetic bar lock 34 is no longer attracted to an aligned position between the auxiliary pole pieces 35 and 36 and is then free to turn. a

A motor control circuit suitable for use with my process timer is shown in Fig. 1. 40 represents a suitable source of supply. The motor has one terminal connected thereto through the wire 4|. The other motor terminal is connected by wire 42 through a safety switch 43 and wire 44 to the movable contact I3 of the process controller and also to one side of a push button switch 45. The corresponding stationary contact 46 of the controller and the other side of push button switch 45 are connected to the other side of supply source 40.

It will be noted that in the initial or zero position of the controller I 4 shown, motor circuit contactor I3 is held open by a short cam projection 41 on t'ite rear of the controller disk I4. Cam projection 41 is preferably of such length that the motor circuit will also be opened thereby at the end of the process timing cycle after the disk I4 has rotated nearly 360 degrees in a clockwise direction and before stop H has come against the rear side of stop I8.

To start the process timer into operation, normally open push button 45 is closed momentarily. "#{Ihe motor I9 starts and revolves controller I4 {in a clockwise direction. Contact finger I3 very shortly closes on contact 46 after which push button switch 45, in parallel, may be released. Magnetic lock 34 is held from rotation by the motor field and hence controller disk I4 is rotated to operate the various other switches associated therewith to time the process to be controlled. At the end of the process timing period stop I! approaches stop I8 and contactor I3 is lifted by the leading edge of cam projection 41. The motor I9 is therefore deenergized, magnetic latch 34 is released and spring 30, which was wound up during the timing operation, rotates controller I4 quickly in a counter-clockwise direction to its initial position. Preferably, when in the initial position, the spring 30 will be under suflicient initial tension to positively return the parts to such initial position with stop finger I1 against the front side of stop I8.

Now, it will be noted that very shortly after the controller I4 starts to return to initial position, the circuit of motor I9 will be closed again and will remain closed until the controller reaches its initial position. This means that the magnetic lock 34 will be energized. However, it does not relock itself from rotation during such return movement of the controller because its momentum prevents this. It is only when it is stationary or approximately so as when rotating very slowly that the flux across pole pieces 35 and 36 is strong enough to align bar 34 therewith and hold it from rotation. During the return movement of the controller the bar 34 acts as a fan brake to limit the return speed and prevent shock at the end of the return movement.

It will be observed that the armature member 34 with pole pieces 35 and 36, together with the field of the motor 31, has the structure of and may be considered a non-self-starting synchronous motor which is energized and deenergized simultaneously with the self-starting timer motor. In the above described operation only the locking action of such non-self-starting synchronous motor atstandstill was utilized. It will be observed, however, if, in the initial starting up of the normal timing cycle of the controller mechanism, I synchronize rotor 34 with the flux pulsations across pole taps 35 and 36 as by spinning it by hand or otherwise, it will allow or cause the central member 20 of the differential to rotate at a definite speed corresponding to the synchronous speed of the non-self-starting motor or, in other words, will lock the central member of the differential at a fixed speed instead of at zero speed. The synchronous speed of such a motor is inversely proportional to the number of rotor poles and a rotor suitable for the synchronous speed desired will be selected.

By such operation I may give to the controller a. definite but quite different time cycle of operation. The pull-out torque of the non-selfstarting synchronous motor is of essentially the same character whether utilized for locking in action at zero or synchronous speed. In either case it should exceed the maximum torque of the spring but be less than the blocked rotor torque of the self-starting motor as such torques are reflected through the drive to the shaft of the nonself-starting motor device.

Again, the stop I8 may be so adjusted to terminate the process timing operation before the motor is deenergized, or the motor switch may fail to open for some reason. In such case the motor will be blocked and the motor torque transmitted directly to the magnetic lock 34 will increase and be sufficient to break it from locking position or synchronous condition and the spring will then return the controller to initial position. In the same way any blocking of the motor due to defective apparatus at any stage of the process timing operation will result in stopping the operation and returning the timer to off or initial position, or, if desired, a slip friction coupling may be suitably embodied in the main spring driving gear train to holdthe timer at a maximum position without pulling out the magnetic fly lock until manually released by opening a switch to cut out the motor, or mechanically disengaging the fly from its magnetic lock thus starting its rotation and allowing the spring to return the mechanism to its initial position.

Failure of the source of supply or opening of the motor circuit for any reason at any stage of the timing operation will stop the timing operation and return the timer to off or initial position. Hence, various safety switches may be placed in the .motor circuit to interrupt the process being timed, in case such switches are opened. The switch 43 is representative. Here 48 may represent a door of the dishwasher the operation of which is controlled by the process device may be designed to have a variety of For example, I may reduce its characteristics. locking torque by reducing its polar effect by a design such as represented in Fig. 3 where a magnetic rim of desired thickness is added. I may employ a magnetically operated brake of the form shown in Fig. 4, where the wheel 50 is the rotary part geared to the differential member 20. 5I are brake shoes hinged at 52 and provided with magnetic pole extensions 53 adapted to be drawn together when flux exists between the auxiliary pole pieces 35 and 36. Fig. 5 shows another possible arrangement where a magnetically operated latch lever 56 engages a notched wheel 55 when the motor is energized to produce flux across the auxiliary pole pieces 35 and 36.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the anesratos which I now consider to represent t sin i bodiment thereoi, but I desire to have it tncier s Said ry m m er stood that the apnaratos shown is only instra A timer meohanis tive and that the invention, may 3. out 1 by other means,

What I claim as new and desire to secure by Letters Patent of the United States is:

1. Timing mechanism comprising:

member, a SBH -SL-EE'ELHQ eieotrio timer motor 3.93

driving said timer member in one direction, a

spring wound by said motor for driving said. QOIlneQiEd i d timer timer member in the opposite direotion, dr v $9 p il Connec ed, to, meohanism including a riifterentai mmugh part connected in driving relation with said 15 rotary part a motor, another part connected in driving re1amotor having auxiliary field 1 tion with said timer member and spring, a non 1S Pmduced when mats? self-starting synchronous motor, sairi sait -start in: and non-seif-starting motors having a oom- Sam aumnary mm @9163 and mnmcm mon energizing Winfiiiig, Hi driving connee= 29 is; relation the third rotary part tion between of said differen Chmrenml and the rotor of m starting synoin T O- 56? nous motor. thiroi rotary part of the olinerentiei 2. Timing mechanism comprising a seifst'=rt- 3'0 anon fi the mam? is energized ing synchronous motor, m teri r synchronous motor, a comm n. energizing? t ing for said motors, a timer member spring, a (inferential having one part conne-o'ted to be driven by selt ste "n t; motor thr reversible driving connection, another e nected in reversible driving relation with said timer member and spring and the third part con nected. in driving relation with. said. non s 1 starting motor, the arrangement being such tnat when said energizing winning is energized the self-starting motor may drive said timer wens her in one direction. wind said spri e when deenergizeci the may zirive Sitifil L rner member in the opposite nirection e e the rotor of the non seii -starting motor tinro N (inferential, said non-selfatarting motor in": a pull-out torque greater than the near i torque of the spring thereon and less than tLe blocked rotor torque of theseif starthig motor thereon.

3. A timer mechanism comprising a rotary timer part having nitial and final rotary" tiny" positions, an electric timer motor for eiri'i said part forward from its initial to final p m tion in a predetermined time, a spring tvr i element, elec ic element returning the timer part rroir. its final to position, a c'iifierentiai through which said ti part and spring are driven by said timer 1 for the purpose of aiiowing the reti timer part to irntiei. position withon driving action on the timer router, and. for conditioning said, oifierential for the tor and return movements of said timer comprising a rotar member oonnecteci in ing relation with. said differential nsegneti 

